carl earned grades of 62, 78, 59, and 89 on four math tests. what is the mean of his grades?\na. 68.5\nb…

Explanation:

Step1: Recall mean - formula

The formula for the mean (average) of a set of numbers $x_1,x_2,\cdots,x_n$ is $\bar{x}=\frac{\sum_{i = 1}^{n}x_i}{n}$. Here, $n = 4$ and $x_1=62,x_2 = 78,x_3=59,x_4 = 81$.

Step2: Calculate the sum

$\sum_{i=1}^{4}x_i=62 + 78+59 + 81=(62 + 78)+(59 + 81)=140+140 = 280$.

Step3: Calculate the mean

$\bar{x}=\frac{280}{4}=70$.

Answer:

B. 70